I want to build a box out of wood. if i'm just trying to grow 4-6 plants in a totally sealed box with ventilation of course then what dimension's would be the best. i'm thinking 3 by 3 and 6 feet tall. Also What would be the best lighting system for a design like that? Would 400 watts be to much? Would a 100 watt metal halide alone work With a hps conversion bulb?